2.8 & 2.81 - WebM / VP9 Encoding error: Additional information: g_timebase.den out of range
The WebM/VP9 Container and Encoder only worked after I had selected a Dimension preset. Then afterwards readjust the render scale percentage and frame rate.



Does this solution make sense? No. But it worked with two different files I had been working on. Defining the dimensions manually for some reason caused the error previously mentioned and also the error, 

CQ level 0 must be between minimum and maximum quantizer value (2-31)

which I received when setting the "Output quality" to "Lossless".